Help Im A Women! Ls400 1990 Shift Wont Engage

[pearlyls4000]

Hello guys and gals! hopefully i get some help. I was driving my car and noticed that it started to dis-engage from DRIVE,,,i was driving on the road about 65mph and notice my speed odo was dropping speed(but i was on the gas peadal steady,) i didnt hear the car roaring cause the radio was blasting. So i stopped at the next red light and when the light turn green i was UNABLE to move forward when i press the gas pedal. I had to turn to car engine off and restart for it to go. I drove about 3 miles and the DRIVE (D) began dis0engaging again. this time i tried to shift into N and shift back to D, but nothing helped , I pulled over coasting and had to restart the engine again just to make it back home.

#1. I check the fluids and they were a bit low. tranny fluid ( i have them re-leveled)

#2. changed battery

#3. drove ok for about 2 days and the issue came back repeating what i said above. BUT THIS TIME it would let me make around the block before the shift dis-engaged. I parked it in the drive way and thats where it has been for about a 4 weeks. I notice to day i went to start it up and the BAttery was Dead?????

does anyone have any idea what this can be,,

1990 lexus ls400 replaced engine with a 96 model it has now about 90K miles on it. with ORIGINAL TRANSMISSION has over 185K

[intakerGS]

There are some thoughts to consider.

- Low transmission fluid reduces the hydraulic pressure load and can cause transmission gear slippage and/or dysfunctional transmission operation. Perhaps a leaking seal?

- some transmission sensors/solenoids are disfunctional.

- The gearsets that comprise the main functional center of the automatic transmission can be worn or frayed.

- Faulty torque converter; fails to pressurize the automatic transmission fluid, causing slip.

- Transmission vacuum hose leaks; fails to keep automatic transmission fluid moving and under set pressure guidelines.

Did you get an engine warning light?

It's strongly adviced to take the car asap to a dealer or trusted (transmission) shop for further diagnose and reading of possible stored engine faultcodes.

When your not recharging the battery, it could be flat in about 4 weeks. This depends also on the state and age of the battery, or perhaps some electrical device (alarm) is eating away some current. You can have this easily checked.

[landar]

Sounds to me like the dreaded broken wires in the trunk lid causing weird tranny problems.

[SRK]

Could be a broken trans mount allowing excessive movement and throwing the linkage out of alignment.

[dcfish]

Could be a broken trans mount allowing excessive movement and throwing the linkage out of alignment.

My thoughts also

[chicofran]

Check your wire harness in the trunk; it's unbelievable but a broken small wire inside that harness can make your car work miserably.

The harness is located in the trunk, at the left side inside a chanel of the hinge covered by a plastic strip. Release the harness, stretch it and close the trunk without the holding strip. Sometimes even the dashboard lights get messed up by it, making it either stay on or flicker and the transmission go off at different speeds. Take the tape off the harness and try to find a "broken" hot wire; have someone else look at your dash to see if the lights flicker.

This problem is very common on th early generation LS-400.

[VBdenny]

The wires in the trunk broke once when my wife was driving the car. Terrible performance and she had to take it out of overdrive to get it to run on the highway. The white wire was completly broken and 1/4" from the other end. After I fixed it once and it broke again, I left the wirepack out of the hinge. IF the "R" light is illuminated then it might be this problem, if not, it's not. I must agree with whoever suggested it above that get the thing on a computer and start from there. In a situation like this, I would take the car to a local Toyota dealer that knows what they are doing. Stay away from Lexus dealers are they will attach a vacuum to your wallet and they have a good one. If the Toyota dealer is owned by the same people as the Lexus dealer, they won't touch it but look for one that isn't. Might be something very simple. Fixing the wire is really pretty easy and many people here could talk you through fixing the wire. I guess we need to know if the "R" light comes one when you press the brake.